Description The CCLME is driven by atmosphere–ocean energy exchange that occurs on many temporal and spatial scales. Large-scale variability is represented by three indices: the status of the equatorial El Niño–Southern Oscillation (ENSO), described by the Oceanic Niño Index (ONI, https://origin.cpc.ncep.noaa.gov/products/analysis_monitoring/ensostuff/ONI_v5.php); the Pacific Decadal Oscillation (PDO, Mantua et al. 1997); and the North Pacific Gyre Oscillation (NPGO, Di Lorenzo et al. 2008). Positive ONI and PDO values and negative NPGO values usually denote conditions that lead to low CCLME productivity, whereas negative ONI and PDO values and positive NPGO values are associated with periods of high CCE productivity.
Indicator Category Climate and Ocean Drivers
Data Steward Schroeder
Erddap Dataset ID cciea_OC_ONI, cciea_OC_PDO, cciea_OC_NPGO
CCIEA timeseries ID cciea_OC_ONI, cciea_OC_PDO, cciea_OC_NPGO
Region NA, NA, NA
Additional Information ENSO events impact the CCLME by modifying the jet stream and storm tracks, changing the nearshore thermocline, and influencing coastal currents that affect poleward transport and distribution of equatorial and subequatorial waters (and species). A positive ONI greater than 0.5°C indicates El Niño conditions, which usually means more storms to the south, weaker upwelling, and lower primary productivity in the CCLME. A negative ONI less than -0.5°C means La Niña conditions, which usually lead to higher productivity. The PDO is related to sea surface temperature (SST), and is derived from sea surface temperature anomalies (SSTa) in the Northeast Pacific, which often persist in “regimes” that last for many years. In positive PDO regimes, coastal SSTa along North American tend to be warmer, while those in the central North Pacific tend to be cooler. Positive PDO values are associated with lower productivity in the CCLME.
The NPGO is a low-frequency variation of sea surface height, indicating variations in the circulation of the North Pacific Subtropical Gyre and the Alaskan Gyre, which in turn relate to the source waters for the CCLME. Positive NPGO values are associated with increased equatorward flow, along with increased surface salinities, nutrients, and chlorophyll-a. Negative NPGO values are associated with decreases in such values, implying less subarctic source water and generally lower productivity.
Figure 1.1: Monthly values of the Oceanic Niño Index (ONI), the Pacific Decadal Oscillation (PDO), and the North Pacific Gyre Oscillation (NPGO), starting 1950 and ending 2024.
(a) ONI
(b) PDO
(c) NPGO
Figure 1.2: Seasonal values of the Oceanic Niño Index (ONI), Pacific Decadal Oscillation (PDO), North Pacific Gyre Oscillation (NPGO) from 1950-2024.
PDO and NPGO both have the 5-year mean below 1 standard deviation (Figure 6.1), with the PDO having a negative 5-year trend.
References
Di Lorenzo, E., N. Schneider, K. M. Cobb, P. J. S. Franks, K. Chhak, A. J. Miller, J. C. McWilliams, et al. 2008. “North Pacific Gyre Oscillation Links Ocean Climate and Ecosystem Change.”Geophysical Research Letters 35 (8). https://doi.org/10.1029/2007gl032838.
Mantua, Nathan J., Steven R. Hare, Yuan Zhang, John M. Wallace, and Robert C. Francis. 1997. “A Pacific Interdecadal Climate Oscillation with Impacts on Salmon Production.”Bulletin of the American Meteorological Society 78 (6): 1069–79. https://doi.org/10.1175/1520-0477(1997)078<1069:apicow>2.0.co;2.
